Aldehyde dehydrogenases (ALDH) constitute a family of enzymes that play a critical role in detoxification of various cytotoxic xenogenic and biogenic aldehydes. There are at least 19 members/isozymes of the ALDH family, where the various isozymes may exhibit different substrate specificity and/or cellular location relative to other members of the family.
Cytotoxic aldehydes derive from a variety of sources. For example, environmental (external) sources of aldehydes include those that result from ethanol consumption, consumption of food sources, or from ingestion of hazardous materials such as vinyl chloride, pesticides, herbicides, etc. Aldehydes that may be cytotoxic can also be produced biologically, e.g., as a result of oxidative stress such as occurs in ischemia, irradiation, or metabolism or bioconversion of cellular precursors such as neurotransmitters and drugs. Accumulation of cytotoxic levels of aldehydes, and/or defects in the ALDH enzyme, has been implicated in a variety of diseases and conditions, or in increased risk of disease development. The range of implicated diseases includes neurodegenerative diseases, aging, cancer, myocardial infarction, stroke, dermatitis, diabetes, and liver diseases.
Mitochondrial aldehyde dehydrogenase-2 (ALDH2) is encoded in the nuclear genome and is transported into mitochondria. ALDH2 is a tetrameric protein composed of four identical subunits, each consisting of 500 amino acid residues. This tetramer can be regarded as a dimer of dimers. The interface between monomers that form a dimer is different and more extensive than the interface between the two dimers that form the tetramer. Each subunit is composed of three main domains: the catalytic domain, the coenzyme or NAD+-binding domain, and the oligomerization domain.
There is a need in the art for modulators of aldehyde dehydrogenase enzymatic activity.